Invasive approaches to the diagnosis of ventilator-associated pneumonia: a meta-analysis.

OBJECTIVE: Ventilator-associated pneumonia remains a major challenge in the intensive care unit. The role for invasive diagnostic methods (e.g., bronchoscopy) remains unclear. We hypothesized that invasive testing would alter antibiotic management in patients with ventilator-associated pneumonia but would not necessarily alter mortality.

DESIGN: Meta-analysis of randomized, controlled trials of invasive diagnostic strategies in suspected ventilator-associated pneumonia and a separate pooled analysis of prospective, observational studies of the effect of invasive cultures on antibiotic utilization in ventilator-associated pneumonia.

SETTING: NA.

PATIENTS: Subjects enrolled in the various clinical trials identified.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: We identified four randomized, controlled trials that included 628 patients. The overall quality of these studies was moderate (median Jadad score of 5) and there was both clinical and statistical heterogeneity among these trials. Ventilator-associated pneumonia was confirmed bronchoscopically in 44-69% of participants, with Pseudomonas aeruginosa and Staphylococcus aureus being the most frequently isolated pathogens. Most subjects (90.3%) received adequate antibiotics; however, in one trial there was a significant difference between the invasive and noninvasive arms with respect to this factor. Overall, an invasive approach did not alter mortality (odds ratio 0.89, 95% confidence interval 0.56-1.41). Invasive testing, though, affected antibiotic utilization (odds ratio for change in antibiotic management after invasive sampling, 2.85, 95% confidence interval 1.45-5.59). Five prospective observational studies examined invasive testing and included 635 subjects. These reports confirm that invasive sampling leads to modifications in the antibiotic regimen in more than half of patients (pooled estimate for rate of alteration in antibiotic prescription, 50.3%, 95% confidence interval 35.9-64.6%).

CONCLUSIONS: Few trials have systematically examined the impact of diagnostic techniques on outcomes for patients suspected of suffering from ventilator-associated pneumonia. Invasive strategies do not alter mortality. Invasive approaches to ventilator-associated pneumonia affect antibiotic use and prescribing.